Support MethodNotAllowed via new EndpointResult

[vkostyukov]

This is essentially an iteration on #883 that instead of capturing a matched method as part of Input, introduces a new EndpointResult case. I like this approach better because:

• It's compliant with https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html (10.4.6)
• It's more efficient (Input remains skinner)
• It keeps a reasonable semantic for Endpoint.apply(Input) for endpoint-mappers so REPL/test environments will return "not-matched" when HTTP verb is different.

Example:

scala> val a = get("foo") { Ok("foo") }
a: io.finch.Endpoint[String] = GET /foo

scala> val b = post("foo") { Ok("post foo") }
b: io.finch.Endpoint[String] = POST /foo

scala> val c = put("foo") { Ok("put foo") }
c: io.finch.Endpoint[String] = PUT /foo

scala> val s = Bootstrap.configure(enabledMethodNotAllowed = true).serve[Text.Plain](a :+: b).serve[Text.Plain](c).toService
s: com.twitter.finagle.Service[com.twitter.finagle.http.Request,com.twitter.finagle.http.Response] = <function1>

scala> Http.server.serve(":8081", s)

And then:

[tw-mbp-vkostyukov finch (vk/match-wo-method)]$ http :8081/bar
HTTP/1.1 404 Not Found
Content-Length: 0
Date: Fri, 16 Mar 2018 20:59:30 GMT
Server: Finch



[tw-mbp-vkostyukov finch (vk/match-wo-method)]$ http POST :8081/foo
HTTP/1.1 200 OK
Content-Type: text/plain
Date: Fri, 16 Mar 2018 20:59:37 GMT
Server: Finch
content-encoding: gzip
content-length: 34

post foo

[tw-mbp-vkostyukov finch (vk/match-wo-method)]$ http PUT :8081/foo
HTTP/1.1 200 OK
Content-Type: text/plain
Date: Fri, 16 Mar 2018 20:59:48 GMT
Server: Finch
content-encoding: gzip
content-length: 33

put foo

[tw-mbp-vkostyukov finch (vk/match-wo-method)]$ http DELETE :8081/foo
HTTP/1.1 405 Method Not Allowed
Allow: PUT,GET,POST
Content-Length: 0
Date: Fri, 16 Mar 2018 20:59:56 GMT
Server: Finch

[vkostyukov]

I want to look into this to see if it could be modeled better so we can avoid asInstanceOf casts in Endpoint.

[codecov-io]

Codecov Report

Merging #927 into master will increase coverage by 0.15%.
The diff coverage is 92.85%.

@@            Coverage Diff             @@
##           master     #927      +/-   ##
==========================================
+ Coverage   82.65%   82.81%   +0.15%     
==========================================
  Files          51       51              
  Lines         767      768       +1     
  Branches       36       39       +3     
==========================================
+ Hits          634      636       +2     
+ Misses        133      132       -1

Impacted Files	Coverage Δ
core/src/main/scala/io/finch/endpoint/param.scala	78.12% <0%> (ø)	⬆️
core/src/main/scala/io/finch/endpoint/header.scala	62.5% <0%> (ø)	⬆️
...e/src/main/scala/io/finch/endpoint/multipart.scala	72.22% <100%> (ø)	⬆️
core/src/main/scala/io/finch/ToService.scala	100% <100%> (ø)	⬆️
core/src/main/scala/io/finch/EndpointResult.scala	81.81% <100%> (+9.09%)	⬆️
core/src/main/scala/io/finch/Bootstrap.scala	90% <100%> (+6.66%)	⬆️
...rc/main/scala/io/finch/syntax/EndpointMapper.scala	100% <100%> (ø)	⬆️
...tee/src/main/scala/io/finch/iteratee/package.scala	95.23% <100%> (-0.22%)	⬇️
core/src/main/scala/io/finch/endpoint/path.scala	95% <100%> (ø)	⬆️
core/src/main/scala/io/finch/Endpoint.scala	75.78% <100%> (-1.22%)	⬇️
... and 1 more

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[vkostyukov]

@sergeykolbasov Do you mind taking a look?

[vkostyukov]

See 10.4.6 here https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html.

Looks like we also need to add Allow header. This means changing the implementation a bit.

[sergeykolbasov]

Sounds like a proper solution to me 👍